How was the period when rome ruled most of europe different from the middle ages?

Politics during the period of Rome is governed by an emperor having their city as a state. It includes the relationship between the landowners having vast lands cultivated by peasants and slaves with the protection of nobles in return for having partial lands for payment. Its economic system is both feudal and slavery. 

The middle ages have the role of a monarchy government and the power of a clergy in the decision making. It has a larger scope of land compared to the Romans. It has a feudal economic system and at the stage of a diminishing slavery system.